Institute of Pharmacology and Toxicology, Beijing, China.
Joint National Laboratory for Antibody Drug Engineering, Henan University, Kaifeng, China.
J Virol. 2024 Sep 17;98(9):e0068524. doi: 10.1128/jvi.00685-24. Epub 2024 Aug 20.
MIL77-3 is one component of antibody cocktail that is produced in our lab and represents an effective regimen for animals suffering from Zaire Ebolavirus (EBOV) infection. MIL77-3 is engineered to increase its affinity for the FcγRIIIa (CD16a) by deleting the fucose in the framework region. The potential effects of this modification on host immune responses, however, remain largely unknown. Herein, we demonstrated that MIL77-3 recognized secreted glycoproptein (sGP), produced by EBOV, and formed the immunocomplex to potently augment antibody-dependent cytotoxicity of human peripheral blood-derived natural killer cells (pNKs), including CD56 and CD56 subpopulations, in contrast to the counterparts (Mab114, rEBOV548, fucosylated MIL77-3). Intriguingly, this effect was not observed when NK92-CD16a cell line was utilized and restored by the addition of beads-coupled or membrane-anchored sGP in combination with MIL77-3. Furthermore, sGP bound to unrecognized receptors on T cells contaminated in pNKs rather than NK92-CD16a cells. Administration of beads-coupled sGP/MIL77-3 complex in mice elicited NK activation. Overall, this work reveals an immune-stimulating function of sGP/MIL77-3 complex by triggering cytotoxic activity of NK cells, highlighting the necessity to evaluate the potential impact of MIL77-3 on host immune reaction in clinical trials.
Zaire Ebolavirus (EBOV) is highly lethal and causes sporadic outbreaks. The passive administration of monoclonal antibodies (mAbs) represents a promising treatment regimen against EBOV. Mounting evidence has shown that the efficacy of a subset of therapeutic mAbs is intimately associated with its capacity to trigger NK activity, supporting glycomodification of Fc region of anti-EBOV mAbs as a putative strategy to enhance Fc-mediated immune effector function as well as protection . Our work here uncovers the potential harmful influence of this modification on host immune responses, especially for mAbs with cross-reactivity to secreted glycoproptein (sGP) (e.g., MIL77-3), and highlights it is necessary to evaluate the NK-stimulating activity of a fucosylated mAb engaged with sGP when a new candidate is developed.
MIL77-3 是我们实验室生产的抗体鸡尾酒的一种成分，代表了一种针对感染扎伊尔埃博拉病毒（EBOV）的动物的有效治疗方案。MIL77-3 通过删除框架区域中的岩藻糖来增加其与 FcγRIIIa（CD16a）的亲和力。然而，这种修饰对宿主免疫反应的潜在影响在很大程度上仍然未知。在此，我们证明了 MIL77-3 识别 EBOV 产生的分泌糖蛋白（sGP），并形成免疫复合物，有力地增强了人外周血来源的自然杀伤细胞（pNK）的抗体依赖性细胞毒性，包括 CD56 和 CD56 亚群，与对照物（Mab114、rEBOV548、糖基化 MIL77-3）形成对比。有趣的是，当使用 NK92-CD16a 细胞系时，并未观察到这种效应，并且通过添加珠结合或膜锚定 sGP 与 MIL77-3 结合来恢复该效应。此外，sGP 结合到 pNK 中污染的 T 细胞上未被识别的受体上，而不是 NK92-CD16a 细胞上。在小鼠中给予珠结合的 sGP/MIL77-3 复合物可引发 NK 激活。总的来说，这项工作揭示了 sGP/MIL77-3 复合物通过触发 NK 细胞的细胞毒性活性发挥免疫刺激功能，突出了在临床试验中评估 MIL77-3 对宿主免疫反应的潜在影响的必要性。
扎伊尔埃博拉病毒（EBOV）具有高度致命性，并引起散发性暴发。单克隆抗体（mAbs）的被动给药代表了一种有前途的 EBOV 治疗方案。越来越多的证据表明，一组治疗性 mAbs 的疗效与其触发 NK 活性的能力密切相关，这支持了对 EBOV mAbs 的 Fc 区域进行糖基化修饰，作为增强 Fc 介导的免疫效应子功能和保护的一种潜在策略。我们的这项工作揭示了这种修饰对宿主免疫反应的潜在有害影响，特别是对于与分泌糖蛋白（sGP）（例如，MIL77-3）具有交叉反应性的 mAbs，并且突出了当开发新候选物时，有必要评估与 sGP 结合的糖基化 mAb 的 NK 刺激活性。
